Heretofore, the conventional arrangement for wrapping a strap around a package employed a chain and sprocket arrangement consisting of four to eight pairs of sprockets for supporting the chain as the chain carries the strap around the package to be strapped. The chain generally consisted of three sections with the outer sections engaged by a pair of spaced sprockets and the inner section carrying a carrier for the strap being wrapped about a package. These sprockets take up considerable space and providing adjustment for the sprockets is a constant problem due to wear and other factors. Of greater concern is the ability to maintain the chain in proper alignment during the many cycles it is used and the high speed at which it is operated. It can be appreciated that if such automatic strapping machines can be provided with a chain drive that is quiet, long wearing, readily adjustable and is positively guided at all times that it would constitute a substantial advance in the art.
In accordance with the present invention, there is employed a system which involves but a single drive sprocket assembly to drive a resilient chain that carries strap about a package to be strapped. The chain during its travel about the package is supported by novel guide shoes which require less space than idlers and provides a unique configuration to insure centering of the chain at all times. In addition, the tension of the chain can be very readily adjusted. Heretofore, chains that have been used have had the tendency to ride out of their support brackets with the result that the chain can become disengaged requiring the machine to be shut down. The chain employed herein involves a unique V-shaped roller configuration which in combination with a plurality of V-shaped guide arrangements used for supporting the chain throughout its travel, insures that the chain will be properly positioned throughout its travel and guarantees long life. The simplicity of the guide design provides for quick and efficient adjustment of the tension of the chain.